Multiporous Peg Research Articles

Antennal sensilla of Didesmococcus koreanus Borchsenius (Hemiptera: Coccoidea: Coccidae) in different instars

To better understand the morphology, structure and function of antennae and antennal sensilla of Didesmococcus koreanus Borchsenius, family Coccidae (Hemiptera: Coccoidea), in the first-instar nymph, adult female and adult male stages, we investigated these stages using light microscopy and scanning and transmission electron microscopy. The results show that the antennae of first-instar nymphs and adult females are similar in morphology and sensilla distribution. The antennae of first-instar nymphs comprise six segments, and each antenna has 24 sensilla of six types: one campaniform sensillum (Ca), eleven smooth aporous trichoid sensilla (St), two basiconic sensilla (Ba), five multiporous pegs (Mp), two smooth multiporous pegs (sMp) and three chaetica sensilla (Ch). The antennae of adult females have six or seven segments, and each antenna has 25 sensilla of the same six types as the first nymphs, but with twelve sensillum St. The antennae of adult males are more developed, and each antenna contains 155–213 sensilla of eight types: 16–34 St, 1 Ca, 2–5 Ba, 1 Johnston’s organ (Jo), 3 knob sensilla (Ks), 5 Mp, 2 sMp and 120–181 multiporous sensilla trichodea (Mt). Based on our analysis, we discuss the possible functions of the antennae and antennal sensilla of D. koreanus in different instars.

External Morphology of Antennae and Mouthpart Sensillae of the Granary Weevil (Coleoptera: Curculionidae)

Abstract The ultrastructure of the antennal and mouthpart sensillae for the granary weevil, Sitophilus granarius L. (Coleoptera: Curculionidae), adult was examined with scanning electron microscopy. The cephalic capsule bears two types of sensillae—a multibranched sensillum and a multiporous peg sensillum. The multibranched sensillum was a structure not previously reported for the granary weevil or any other insect species, and is distinguished by its torpedo-shaped appearance. The multiporous peg sensillae, formed from multiple straight tubules, are distributed on the distal one-third of the rostrum. The mouthparts bear two types of sensillae—the multiporous peg sensillae on the labrum and mandibles, and short basiconic sensillae on the labial palps. The antenna consists of eight segments arranged on the scape, pedicel, and flagellum. Each antennal segment bears sqaumiform sensillae, and five types of sensillae were identified on the club segment. These sensillae are a trichodea Type I, trichodea Type I...

Antennal sensilla and their nerve innervation in first‐instar nymphs of Porphyrophora sophorae Arch. (Hemiptera: Coccomorpha: Margarodidae)

Porphyrophora (Hemiptera: Coccomorpha: Margarodidae) is a genus of soil-inhabiting scale insects. The antennal sensilla and their innervation in the first-instar nymphs of Porphyrophora sophorae were studied using light microscopy and scanning and transmission electron microscopy to understand the function of these sensilla and determine the sensillar innervation feature on these small antennae. The results show that the six-segmented antennae of these nymphs have 20-23 sensilla which can be morphologically classified into seven types, for example, one Böhm's bristle (Bb), one campaniform sensillum (Ca), one Johnston's organ (Jo), 13-16 aporous sensilla trichodea (St), two coeloconic sensilla (Co), one straight multiporous peg (Mp1), and one curvy multiporous peg (Mp2). According to their function, these sensilla can be categorized into three categories: mechanoreceptors, that is, Bb, Ca, Jo, and St; thermo/hygroreceptors, that is, Co only; and chemoreceptors, that is, Mp1 and Mp2. The dendrites that innervate the Mp1, Mp2, and Co sensilla combine to form a large nerve tract (NT1) in the antennal lumen. Because NT1 extends through and out of the antenna, the somata of these neurons are present in the lymph cavity of the insect's head. The dendrites that innervate the mechanoreceptors form another nerve tract (NT2). The somata of these neurons are located inside the scape and pedicel. J. Morphol. 277:1631-1647, 2016. © 2016 Wiley Periodicals, Inc.

The structure and morphogenic changes of antennae of Matsucoccus matsumurae (Hemiptera: Coccoidea: Matsucoccidae) in different instars

To better understand the functioning and morphogenic changes of the antennae of Matsucoccus matsumurae (Kuwana) in different instars, the antennae are examined using light microscopy, scanning and transmission electron microscopy. The results show that the antennae of M. matsumurae display three different styles in morphology and sensillar distribution in different instars. The antennae of first instar nymphs are relatively simple, including one campaniform sensillum (Ca), four smooth aporous trichoid sensilla (SAt), two intersegmental sensilla (Ins), two coeloconic sensilla (Co), three multiporous pegs (Mp) and four uniporous pegs (Up). The antennae of adult females and third instar male nymphs both possess similar antennae, and exhibit seven types of sensilla. Adult female antennae have in total 82–108 sensilla, including 9–16 Böhm's bristle (Bb), 3–7 Ca, 50–75 SAt, 0–3 Ins, 3–10 Co, 8 Mp and 5 Up, whereas third instar male nymph antennae possess approximately 62–79 sensilla. Adult male antennae are the most developed, possessing 259–312 sensilla, including 7–15 Bb, 2–5 Ca, 7–11 grooved aporous trichoid sensilla, 4–9 SAt, 0–3 Ins, 2–7 Co, 23–29 knobbed seta sensilla, 179–230 multiporous trichoid sensilla and 8 Mp. Based on these results, the main functions and morphogenic changes of antennae M. matsumurae in different instars are discussed.

Distribution of the sensillae of the red palm weevil, Rhynchophorus Ferrugineus (Oliv.) (Coleoptera: Curculionidae)

The distribution of the types of sensillae in the adult red palm weevil, Rhynchophorus ferrugineus (Oliv.) (Coleoptera: Curculionidae), was studied using scanning electron microscopy. Five types of sensillae can be identified on the antenna, with no apparent differences between sexes. These are: multiporous peg sensillae, sensillae trichoïdea (I and II); sensillae basiconica (type I, II and III) and sensillae styloconica. The distal segment of the maxillary palp bears 22 sensillae basiconica in the female, 13 in the male.The upper and lower incisor cusps of the mandibles of the male are relatively longer and more rounded, with an angle of 45° or more where the inner margins of the cusps meet. In the female, the upper and lower cusps are slightly shorter, with an angle of about 45°. In the buccal cavity of females, groups of finger-like sensillae basiconica of various length and shape project toward the centre of the oral opening. In the male, multiporous peg sensillae are found. Sensillae trichoidea are present on the ventral and dorsal sides of the first, second and third tarsal segments distally. These are much denser on the male than the female. On the terminal (9th) abdominal segment of the ovipositor, sensillae are distributed on the dorsal plate, medial plate, ventral plate and anal leaflets (paired). Sensillae of four types occur on the anal leaflets.

The fine structure of uniporous and nonporous pegs on the distal antennal segment of the diving beetle Graphoderus occidentalis Horn (Coleoptera: Dytiscidae)

The terminal segment of the antenna of the predaceous diving beetle Graphoderus occidentalis Horn bears approximately 50 sensilla of nine different types. There are six types of uniporous chemosensilla, one type of nonporous mechanosensitive peg, and two types of multiporous pegs. Two types of uniporous pegs, which occur only at the antennal tip, have features of both contact chemosensilla and thermo- and hygro-sensilla. Three other types that occur only on the terminal segment below the apex also exhibit some features of chemosensilla and thermo- and hygro-sensilla. The sensilla are innervated by one to four neurons and most are ensheathed by two accessory cells. Four types of sensilla exhibit elaborate sheath cell configurations and secretions associated with their sinus that may reflect an adaptation to an aquatic or a dual aquatic–terrestrial habitat. All are atypical of generalized insect sensilla in having portions of the proximal dendrites and axons as well as the entire neuronal perikarya unsheathed and exposed to the hemocoel. The neuronal perikarya of two sensillar types contain virus-like particles.

Distribution and innervation of sensilla on the mouthparts of the carnivorous stonefly nymph, Paragnetina media (Walker) (Plecoptera: Perlidae)

The external morphology and distribution of various types of sensilla on the mouthparts of the nymphs of Paragnetina media are described, based on light and scanning electron microscopy. Hairs of various types are arranged in distinctive patterns on each mouthpart. Scolopophorous sensilla, each consisting of a pore canal and two bipolar neurons, are present in the mandibular teeth. The elliptical type of campaniform sensilla, multiporous columnar pegs, and nonporous sensilla are concentrated on the segments of the maxillary and labial palps. The tips of the maxillary and labial palps bear a cluster of uniporous multidigitate pegs, a multiporous peg, a circular type campaniform sensillum, and several nonporous sensilla. Nonsocketed uniporous pegs crown the tip of galeae and are also scattered over the surface of the glossae and paraglossae. Possible functions of these sensilla are discussed. A cleaning method is described to visualize details with the scanning electron microscope.

Innervation and fine structure of antennal sensilla of Simuliidae larvae (Diptera: Culicomorpha)

Light, scanning electron, and transmission electron microscopy were used to investigate fine structure and innervation of antennal sensilla of Simuliidae larvae with particular attention to a bacteria-covered structure superficially similar to chloride-absorbing cells of other aquatic insects.Eight sensilla of five morphological types innervated by a total of 22 neurones are described. A single uniporous cone sensillum, with five distal dendrites in a common dendritic sheath is on the antennal apex. Two multiporous peg sensilla, each with two distal dendrites in separate, but fused dendritic sheaths, are at the base of the distal antennal article. Near the base of the proximal antennal article on the membranous antennal base is a single trichoid sensillum, probably with a single distal dendrite. Ventral to the base of the antennal articles is the bacteria-covered structure, shown here to be a multiporous sensillum, with five distal dendrites invested in a fused dendritic sheath, which has a foamy appearance and is fenestrated. A pore tubule system is described for this sensillum, the first time for sensilla of any aquatic insect. The sensillum is internally surrounded by a heavily cuticularized capsule which is supported laterally by buttresses and is penetrated by a canal, through which the dendrites enter.Because of a peculiar feature of moulting in Simuliidae larvae, the sensillar sinus of this sensillum is open to the moulting space between cuticle and epidermis. The cellular portion of that sinus is closed off.Probable gram-negative bacteria on this sensillum appear to prefer sensillar exudate. Comparison of chloride concentration in this sensillum, with that of another multiporous sensillum, using energy-dispersive X-ray spectrometry, showed no significant differences, indicating no enhanced chloride absorbing function for the former sensillum.The bacteria-covered sensillum is always closely accompanied by a trichoid sensillum innervated by a single distal dendrite with a tubular body.Two small uniporous peg sensilla located anteroventrally on the membranous antennal base have three distal dendrites each. In the large ciliary sinuses these dendrites become highly lamellated, bound with pleated septate junctions, and associated with concentrations of mitochondria. It is suggested that these lamellae have a secretory–absorbtive function.On the basis of similarity in structure and number, tentative homologies with antennal sensilla of other Culicomorpha larvae are suggested.